DSLR astrophotography by Sergi Verdugo
The Crescent Nebula
Exposure: 28×600″ @ ISO 800
Telescope: Skywatcher Newton 8″ f5 with Baader MPCC
Filter: Baader UV/IR cut 2″
Mount: Skywatcher EQ6 Pro
Camera: Modded Canon 350D in cooler box
Date: 21st August 2009
Location: Rasos de Peguera (Barcelona, Spain)
Comments: My objective in this image was to get the OIII region of the Crescent Nebula clearly visible.
The Crescent Nebula, also known as NGC 6888 or Caldwell 27, is an emission nebula in the Cygnus constellation, about 5000 light years away. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray emitting temperatures.